Flow preventer for oil wells



June 27, 1939. w K. EDWARDS ET AL FLOW PREVENTER FOR OIL WELLS FiledJan. 22, 1958 2 Sheefs-Sheet l v June 27, 1939. w. K. EDWARDS ET AL2,163,976

FLOW PREVENTER FOR OIL WELLS 2 Sheets-Sheet 2 of a v, 1 w 1 m ":1 21 g 55 m W% a a M m i g 4 H Z w .,w TL w Patented June 27, 1939 UNITED STATESPATENT OFFICE' 2,183,976 FLOW PREVENTER FOR OIL WELLS William K.Edwards, Big Spring, and Orland Thompson, Wickett, Tex.

Application January 22, 1938, Serial No. 186,456 10 Claims. (Cl. 166-13)This invention relates to devices of that type a pump down plugembodying the invention is which are pumped down into an oil well forillustrated. preventing the how of oil upwardly through the In thedrawings: well tubing while certain repairs or replacements Figure 1shows the invention, partly in vertical of the tubing are being made, orfor any other section and partly in elevation, with the exreason it isfound necessary to withdraw the well panding cone for the plugwithdrawn,

tubing from an oil well, without permitting the Figure 2 is a viewsimilar to Figure l, but

oil to escape from the well. showing the parts in a different position;that is,

Such devices are known in the oil well art as with the rubber packer andslips expanded for pump down plugs or flow preventers, and the holdingthe plug in position in the well; 10' present invention has to do withcertain impor- Figures 3 and 4 illustrate the device in two tantimprovements in such devices. separate parts, with the mandrel andpacker parts The withdrawal from the well of the tubing, in section, andthe valve and valve stem parts in for repairs or otherwise, renders itnecessary to elevation; temporarily stop the flow of oil from belowFigure 5 is a Section on the e of while such repairs or replacements ofthe tubing ure 3;

sections are being made, and while devices of Figure 6 is a Se i n 0 theline this general character have been heretofore cone I structed, so faras applicants are aware,they have Figure '7 is a section on the line1--'| of Fi not operated with that certainty which is necesli e and dsary to insure the complete cutting off of the oil Figure 3 is a Sectionn the e F ure from the well, eithe he th tubing i with- The mandrel I,shown in elevation in Figures 1 drawn or there is a leakage through thetubing. and 2, and in Section in Figures 3 and 4, is hollow The presentinvention is devised for the purand the upp Portion thereof is e a ypose of insuring more certainty of the stoppage threaded and issurrounded by a rubber 3 which 2 f the flo by th pump-down lu nd moreisheld in position between rings 6 and 1, threadover, to enable the welloperator to remove the d to t man ehwhile a cap 2 is threaded to plugwhen desired, the extreme upper end portion of the mandrel A further andvery important bj t of th and provided with apertures 32 for conveyingcirpresent improvements, however, resides in a t s liquid o th terior ofthe mandrel. 30 mean for flushing th ll through th p p- The lowerportion of the mandrel is provided down plug or flow r nt r, assometimes after externally with threads and receives a lower rubthe plughas been pumped or forced to the bottom 4, Whose lower end is Secured ina ring of the tubing it has been found necessary to threaded t0 themandrel, the pp P t o o 35 pump or cir ulat fl id th u h it, i order tthe rubber 4 being herein shown as secured with- 35 free the tubingwhich may be obstructed or sandin an annular ec s in a tapering enlarlocked, with a view t aeeemphshmg t pur- I! of the mandrel. A packersleeve l6 of rubber pose applicants provide nd r th present i or othersoft material, surrounds the mandrel vention a hollow mandrel in theflow preventer and i5 D Q With a longitudinal bo e f tt ng whichcontains a valve stem having thereon a Over the enlarged tepelingpertion O the 4 valve which is forced to its seat in the lower pormandrand extendmg upwardly therefrom a mm t the plug by a spring The tensionof this substantial distance. The upper end of the rubber packer I6 isconnected to a ring Ilia which s rm ma be so re ulated that while itwill rgsistgthe Zpemng of valve under the pres surrounds the mandrel andslides thereon. A ta- Sures which force the plug down into the well,pered sleeve l8 surrounding the mandrel is con- 5 the spring will yieldwhen a higher pressure is nected at its lower end portion with the ringlea, and extending upwardly from the tapered portion apphed tqthe mudfor t purpose of permlttmg of the sleeve a cylindrical part thereof isprovided circulamon the field through the Valve at opposite sides withdiametrical slots lBb, the

131115 when extreme upper extension of the cylindrical portion 50 Theforeemng, and other Important and of the sleeve I8 terminating in a ringl8c, the uable Obje t d advantages of he invention sleeve, itscylindrical extension and terminal ring will be more fully understoodfrom the following being free to slide for a limited distance upondetailed description, when considered in connecthe exterior of themandrel, for a reason which tion with the accompanying drawings, inwhich will be hereinafter explained. 5'5

Surrounding the sleeve l8 are a plurality of slips 20 which are hereinshownas integrally formed with a collar 2i, the slips being separatedfrom each other by slots, as shown, and leaf springs 22 extend from thecollar 2| and have their outer, end portions bearing against the slipsto normally hold the latter contracted and out of gripping engagementwith the interior of the well tubing, which latter is indicated by thenumeral 50. The slips 20 are, as usual, formed with annular teeth asshown in order that they may when properly spread, grippingly engage theinterior of the tubing so as to prevent the flow preventer from beingblown outwardly by the pressure within the well, after the pressure fromabove has been dimin- Ihe interiorwalls of the slips are tapered asshown, from a large bore at the lower end to a small bore at the upperportion, as will be clear from the drawings, such tapering interiorsurface of the slips causing, through engagement with the taperedexterior surface of the sleeve l8, when the latter moves upwardlyrelatively to the slips, due to the pressure from below, a spreadingmovement of the slips outwardly whereby they are made to engage theinterior of the well tubing to thereby arrest outward movement of theflow preventer as an entirety. When the pressure from the well below isless than the pressure from above, due to the pumping of the fluiddownwardly, the slips will be out of wedging engagement with the surfaceof the sleeve l8, and the springs 22 will effect a contraction of theslips, thereby leaving the flow preventer free for movement in adownward direction. This occurs while the pump is operating to force thefluid against the flow preventer to cause it to move downwardly in thewell to that point where it is desired to shut off the well flow fromthe tubing.

When the parts are as shown in Figure 1 of the drawings, the mandrelwith its tapered portion I2 is withdrawn a slight distance below thepacker sleeve l6 and the tapering sleeve I8 is in lowered position, outof wedging engagement with the slips 20 so that both the packer sleeveand slips are withdrawn inwardly, and out of contact with the interiorof the well tubing. This is the position that the parts assume when theplug or flow arrester is being pumped down into the well by thehydrostatic pressure effected by the pump. In the drawings we have shownof the pumping fluid lshed, or stopped.

the parts of the pump down plug in Figure 2 as in that position whichthey assume when the hydrostatic pressure from above is diminished orentirely suspended, whereby the pressure of the oil from below will thepacker l6 against the wall of the well and at the same time the taperedsleeve will spread the slips 20 outwardly against, and in grippingengagement with, the well tubing so that the plug is prevented frommoving outwardly and the packing l6 effects a tight joint between thewell and plug to prevent outward escape of the oil.

As a means for effecting a circulation of the fluid through the pumpdown plug we have, under this invention, provided a hollow mandrel, andsliding interiorly thereof, as shown in Figures 3 and 4, a valve stem isprovided. This valve stem is made in two parts, 21 and 28, the part 2!being at its lower end provided with a bore which receives the upper endportion of the section 23; as shown in Figure 4. A pin 49 extendstransversely through an aperture in the lower part 28 of the valve stem,and acts as a limiting means against relative movement of the twoportions of the stem, in a direction towards each other. The telescopic,sliding connection between the two members of the valve stem, however,permits relative movement of these the lower end portion of the mandrel,

valve with ports 3| for the exit of water of circulation. Thetelescopic, sliding connection or-slip joint between the two members ofthe valve stem is for the purpose of permitting the valve to be forcedoutward against the tension of the spring to permit the fluid to withoutaffecting or mov- A thimble 34 is externally threaded to engage aninternal thread in the lower portion of the member 33, said thimblebeing provided with a central bore and having apertures I [la in thelower portion thereof. A spiral spring 30 is located in the member 33and confined between the lower face of the valve and the thimble 34. Thelatter serves as a. tension of the spring 30, and hence, for determiningby such tension the hydrostatic pressure which the valve will resistbefore opening to permit circulation of the fluid.

The upper portion 21 of the valve stem is provlded with an enlargementor shoulder 38, and at a suitable distance therebelow, with a key 25,extending transversely through a slot in the stem. This key passesthrough diametrical guide slots in the mandrel I, the upward extensionof the sleeve l8, and the slips 20.

The upper end portion of the stem part 21 is externally threaded toreceive an internal and externally threaded cap 35. A sleeve 26 is shownas in threaded engagement with the external thread of this cap. .Thissleeve is the size of the average pumping rod and is for the purpose offishing the plug, when necessary to remove it, the diameter of thesleeve conforming to the tubing slips, or fishing tool, that is incommon use. 26 may be and preferably is or some soft metal, and beingthreaded to the cap 35, it may be broken loose from the plug by upwardpull on the line, in case the plug should be so stuck in the well thatit would be impossible to pull the same, in which event, as will beobvious, the internal threads of soft or Babbitt metal in the sleeve 20would strip.

Preferably, and as herein shown, the packer I6 is lined interiorly witha plurality of strips 48, which act as a reinforcing liner for thepacker, and delay the wearing out of the packer through contact with thetapering portion l 2 of the mandrel, after repeated use of the plug.

It will be observed that during the operation of the oil pressure fromthe well the swab rubber 4 acts as a piston and effectively permits thepressure to not only spread the slips against the tubing to arrestmovement of the flow preventer, but additionally, will effect thespreading of the packer sleeve l6 when the oil pressure from the wellpredominates over the pressure from the eifects an upward movement ofthe mandrel, thereby causing the tapering portion I2 to spread thepacker l6 and thus effecting an absolutely liquid-tight joint,preventing any flow of oil beyond the flow preventer. Also, it isapparent that when the plug is being forced downward into the well theupper swab rubber 3 is that element of the plug upon which the pumppressure acts to force the plug downward into the well, preliminary tothe release of pressure from above, under which circumstances the wellpressure predominates.

When it is desired to circulate fluid through the plug, the pressurefrom the pump is simply increased to that point where it will overcomethe resistance of the spring 30, thus forcing open the valve 29 andpermitting the liquid to circulate.

Unless the pressure from above is sufficient to open the valve duringthe normal operation of the plug down into the well, the valve remainsclosed, thus permitting the plug to be moved downwardly to that pointwhere it is desired to cut off the flow of the oil. It is commonpractice in well tubing to have a pin welded through the bottom ofthe'tubing to from going out into the well, and this pin will arrest theplug of the present invention when it reaches the bottom of the well, ifit is ever forced down that far.

When it is desired to remove the plug from the well, fishing means; suchas the sleeve 28, are threaded to the cap 35, or upperportion of thevalve stem, which latter is pulled upward. Preliminary to this operationit is usual with this device to first jar it down slightly, thus givingthe slips a chance to release from gripping engagement with the interiorof the tubing, then upon an upward pull being applied to the valve stem,the key 25 will move upwardly in the slots in the mandrel, slip expandersleeve, and slips; and will lift the slips and packer up to the bottomface of the sleeve 1 attached to the swab rubber, this action freeingthe plug from engagement with the well tubing. A further movement of thevalve stem upward will cause engagement between the shoulder orenlargement 3B and the upper interior terminal wall of the cap 2 whichaffords a positive engagement between the valve stem shoulder 38 and theplug, thus enabling the latter to be removed from the well. As someresistance may 'be encountered in this operation, it will be seen thatthe positive engagement between the stem and cap, which latter is anextension of the mandrel, will relieve created by the friction inlifting the plug out of the tubing, placing the entire strain upon thevalve stem shoulder and mandrel cap. During this operation it will beapparent that the telescopic connection between the parts 21, 25 of thestem, being shorter than the upward distance traveled by the stem beforethe shoulder 28 contacts with the cap, will cause a separation of thestem parts. when the parts are re-inserted, however, a reverse movementof the stern will permit reengagement of the two stem parts by reason ofthe fact that the shoulder 38 will act as a guide, thus insuring themovement of the lower end of the part 21 over the upper end of the part28 to restore these elements to their normal condition. The downwardpressure of water on the valve 29 does not move that valve a sufllcientdistance to cause separation between the two parts of the stem.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent is:

1. In a device of the class described, the comprevent various tools thekey 25 of the load bination of a hollow mandrel having a taperedportion, a plurality of slips surrounding said man'- drel, a wedgemember slidable on the mandrel and engaging a wedging surface interiorlyof the slips, pistons at the opposite ends of the mandrel, a packersleeve on said mandrel having a bore to engage the tapered portionthereof, whereby upward pressure on the mandrel will cause the slips toengage a well casing and will also effect a spreading of the packersleeve against the tubing,

and a downwardly facing valve seat in said mandrel, a valve on saidseat, a spring for holding said valve normally seated, said valvearranged to open under hydrostatic pressure to permit a circulation offluid through the device.

2. In a device of the class described, the combination of a hollowmandrel, means carried by said mandrel and movable longitudinallythereon for effecting engagement between the mandrel and the welltubing, said means being operated by pressure of the oil from the well,and a spring seated valve within said hollow mandrel provided with anupwardly extending stem formed of two slidingly connected partspermitting free movement of the lower part with the valve underhydraulic pressure from within the mandrel to permit circulation offluid therethrough.

3. In a flow preventer, a hollow mandrel provided interiorly with avalve seat, a valve stem and valve within said mandrel, the valve beingnormally seated by a spring, means operable by pressure from the well toefiect a locking of the mandrel to the well tubing, means operated bythe same pressure for eflecting a tight joint between the flow preventerand well, said spring being of suillcient strength to hold the valveclosed during the application of that amount of pressure necessary toforce the flow preventer down into the well but arranged to yield andpermit the valve to open under excess fluid pressure from above to causecirculation of said fluid through the flow preventer.

4. In a flow preventer, a hollow mandrel, pistons on the mandrelarranged near opposite end portions thereof, a tapering member on saidmandrel, a packing sleeve on said mandrel, slips carried by the mandrel,a wedging element for spreading said slips operable when the mandrel ismoved upward by pressure within the well, a valve seat in said mandrel,a valve stem and valve in said mandrel, and a spring for seating saidvalve, said spring being of strength sufficient to prevent the valvefrom being unseated by pressure from above until a predeterminedpressure has been exceeded, thus permitting circulation of the fluiddownwardly and through the flow preventer.

5. In a flow preventer, a hollow mandrel, packing means and slipssurrounding said mandrel, means sliding upon said mandrel for effectingoutward movement of the packing and slips due to pressure from the well,a two-part valve stem the members of which are in telescopic engagementlocated in said mandrel, a valve carried by the lower section of saidstem, a spring for normally holding said valve to its seat, and ashoulder on the upper portion of said stem arranged for engagement withan abutment carried by a portion of the mandrel to permit relativeengagement between said portion of the valve stem and mandrel inwithdrawing the flow preventer from the well.

6. In a flow preventer, a hollow mandrel proprovided with a valve seat,a two-part valve stem in said mandrel having telescopic connection witheach other to permit relative movement of said parts to each other, aspring pressed valve carried by one of said valve stem parts andarranged to be held on said valve seat by its spring, the other portionof said valve stem provided with a transversely extending key, and witha shoulder above said key, said key arranged for movement through slotsin said mandrel, and said shoulder being arranged for engagement with anabutment carried by the mandrel for withdrawing the flow preventer froma well.

7. In a flow preventer, a hollow mandrel provided with a valve seat andan externally tapered portion, a plurality of slips surrounding saidmandrel, a tapering sleeve slidable on the mandrel and engaging awedging surface interiorly of said slips, pistons on the opposite endsof said mandrel, a packer sleeve on said mandrel having a bore to engagethe tapered portion thereof, whereby upward pressure on the mandrel willcause the slips to engage a well casing and movement of the mandrelthereafter under pressure against the lower piston will effect aspreading of the packer sleeve in engagement with the well casing, avalve stem in said mandrel provided with a shoulder and having atransversely extending member which slides in slotted portions in saidmandrel wedge member and slips and arranged upon upward movement of thestem to lift the slips and packer upwardly and thereafter throughengagement of the shoulder on the stem with an abutment in said'mandrelto efl'ect withdrawal of the flow preventer from the well.

8. In a flow preventer, the combination of a hollow mandrel providedwith an enlarged conical portion, expansible slips surrounding saidmandrel, a packer surrounding the conical portion of said mandrel, meansfor spreading said slips upon upward movement of the mandrel, pistonslocated on opposite ends of the mandrel, a valve stem having avalvethereon within said mandrel, a spring normally holding said valveagainst a seat therein, and ports arranged for the entrance of fluidnear one end of the mandrel and for the exit of said fluid near theopposite end of said mandrel.

9. In a flow preventer, a hollow mandrel provided with means forcirculating fluid therethrough, means for arresting upward movement ofsaid mandrel actuated by pressure from the well, pistons located nearopposite ends 01' the mandrel, a stem in said mandrel, a combined stopand guide on said stem for engagement with an abutment on the mandrel atthe upper terminal of movement of the stem when withdrawing the latterfrom the well, and a sleeve having soft metal internal threads forthreaded engagement with said valve stem to provide a rupturableconnection between said stem and sleeve upon the application of anupward force to withdraw the flow preventer from a well.

10. In a flow preventer, a hollow mandrel provided at its ends withmeans permitting the entrance and exit of circulating fluidtherethrough, a packer and slips surrounding said mandrel, means slidingupon said mandrel for effecting outward movement of the packing andslips due to pressure from the well, a two-part valve stem in saidmandrel the members of which are in telescopic connection, a valvecarried by the lower section of said stem, a string for normally holdingsaid valve against a valve seat in said mandrel, and a projection on theupper portion of said stem arranged for engagement with an abutmentwithin the mandrel to permit withdrawal of the mandrel from the wellwhen an upward pull is exerted upon the upper portion of the valve stem.

WILLIAM K. -EDWARDS. ORLAND THONIPSON.

